Detection of Multiple Intracellular Bacterial Pathogens in Haemaphysalis flava Ticks Collected from Hedgehogs in Central China

Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus)

BACKGROUND

The endangered Formosan black bear (Ursus thibetanus formosanus) is the largest native carnivorous mammal in Taiwan. Diseases, poor management, illegal hunting, and habitat destruction are serious threats to the survival of bear populations. However, studies on the impact of diseases on bear populations are limited. Therefore, this study aimed to establish a database of the hematological and plasma profiles of free-ranging Formosan black bears and investigate the occurrence of ectoparasites, blood parasites, and vector-borne pathogens.

METHODS

Formosan black bears were captured in Yushan National Park (YNP) and Daxueshan Forest Recreation Area (DSY) in Taiwan. Blood samples were collected from each bear for hematological analysis and plasma biochemistry using a hematology analyzer. Parasites and pathogens were detected using a thin blood smear with Wright-Giemsa staining and polymerase chain reaction (PCR) assay. Additionally, macroscopic ectoparasites were collected from bears to detect blood parasites and other pathogens. Moreover, the relationships between the bear variables (sex, age, and occurrence of parasites or pathogens), ectoparasites, and infectious agents were also analyzed.

RESULTS

In all, 21 wild bears (14 in YNP and 7 in DSY) were captured and released during the satellite tracking studies. Hematological analysis and plasma biochemistry indicated significant differences in white blood cells (WBC), segments, creatine kinase (CK), and lactate dehydrogenase (LDH) levels between foot snare and culvert-captured bears. Additionally, there were significant differences in total plasma protein (TPP), creatinine, Ca2+, Mg2+, and K+ levels between male and female bears. Moreover, pathogen-infected bears had significantly higher erythrocyte sedimentation rate (ESR; 30 min and 1 h) and globulin levels than uninfected bears. In total, 240 ticks were collected from 13 bears, among which eight adult tick species were identified, including Haemaphysalis flava, Haemaphysalis hystricis, Amblyomma testudinarium, Ixodes ovatus, Dermacentor taiwanensis, Haemaphysalis longicornis, Ixodes acutitarsus, Amblyomma javanense, and nymphs belonging to Haemaphysalis spp. PCR revealed that 13 (61.90%) and 8 (38.10%) bears harbored Hepatozoon ursi and Babesia DNA, respectively. Among the ticks examined, 157 (65.41%) and 128 (53.33%) samples were positive for H. ursi and Babesia, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first study to establish a database of the hematological and plasma profiles of wild Formosan black bears and investigate ectoparasite infestation and Hepatozoon and Babesia spp.

INFECTION

In conclusion, these findings may serve as a reference for monitoring the health and population of locally endangered bears.

Analysis of Differences in Characteristics of High-Risk Endemic Areas for Contracting Japanese Spotted Fever, Tsutsugamushi Disease, and Severe Fever With Thrombocytopenia Syndrome

Background

Tick-borne infections, including tsutsugamushi disease, Japanese spotted fever, and severe fever with thrombocytopenia syndrome (SFTS), are prevalent in East Asia with varying geographic distribution and seasonality. This study aimed to investigate the differences in the characteristics among endemic areas for contracting each infection.

Methods

We conducted an ecologic study in Japan, using data from a nationwide inpatient database and publicly available geospatial data. We identified 4493 patients who were hospitalized for tick-borne infections between July 2010 and March 2021. Mixed-effects modified Poisson regression analysis was used to identify factors associated with a higher risk of contracting each tick-borne disease (Tsutsugamushi, Japanese spotted fever, and SFTS).

Results

Mixed-effects modified Poisson regression analysis revealed that environmental factors, such as temperature, sunlight duration, elevation, precipitation, and vegetation, were associated with the risk of contracting these diseases. Tsutsugamushi disease was positively associated with higher temperatures, farms, and forests, whereas Japanese spotted fever and SFTS were positively associated with higher solar radiation and forests.

Conclusions

Our findings from this ecologic study indicate that different environmental factors play a significant role in the risk of transmission of tick-borne infections. Understanding the differences can aid in identifying high-risk areas and developing public health strategies for infection prevention. Further research is needed to address causal relationships.

Current Status and Challenges Associated with Tick-Borne Pathogens and Diseases: Where Do We Stand?

Lyme Borreliosis (LB), caused by Borrelia burgdorferi sensu lato (s [...].

Pathogenic Rickettsia, Anaplasma, and Ehrlichia in Rhipicephalus microplus ticks collected from cattle and laboratory hatched tick larvae

BACKGROUND

The order Rickettsiales contains a group of vector-borne gram-negative obligate intracellular bacteria, which often cause human emerging infectious diseases and economic losses for dairy and meat industries. The purpose of this study is to investigate the distribution of the pathogens including Rickettsia spp., Anaplasma spp., and Ehrlichia spp. in the order Rickettsiales in ticks from Yueyang, a prefecture-level city of Hunan Province in Sothern China, and assess the potentiality of transovarial transmission of these rickettsial organisms.

METHODS

Ticks were collected from cattle in a farm in Yueyang City and the tick DNA was used as template to amplify the htrA, rrs, gltA, ompA and ompB genes of Rickettsia as well as rrs and groEL genes of Anaplasma and Ehrlichia.

RESULTS

All ticks (465) collected were the cattle tick, Rhipicephalus microplus. PCR showed the minimum infection rate (MIR) was 1.5% (7/465) for Candidatus Rickettsia xinyangensis, 1.9% (9/465) for C. Anaplasma boleense, 1.3% (6/465) for Anaplasma platys, 0.6% (3/465) for A. marginale, and 1.17% (2/465) for each of A. bovis, Ehrlichia minasensis, and a non-classified Ehrlichia sp. A human pathogen, C. Rickettsia xinyangensis and A. platys were detected in 100% (3/3) and 33.3% (2/6) laboratory-hatched larval pools from infected females respectively.

CONCLUSION

Our study revealed a diversity of pathogenic rickettsial species in R. microplus ticks from Hunan Province suggesting a threat to people and animals in China. This study also provided the first molecular evidence for the potential transovarial transmission of C. Rickettsia xinyangensis and A. platys in R. microplus, indicating that R. microplus may act as the host of these two pathogens.

Microorganisms associated with hedgehog arthropods

Hedgehogs are small synanthropic mammals that live in rural areas as well as in urban and suburban areas. They can be reservoirs of several microorganisms, including certain pathogenic agents that cause human and animal public health issues. Hedgehogs are often parasitized by blood-sucking arthropods, mainly hard ticks and fleas, which in turn can also carry various vector-born microorganisms of zoonotic importance. Many biotic factors, such as urbanization and agricultural mechanization, have resulted in the destruction of the hedgehog's natural habitats, leading these animals to take refuge near human dwellings, seeking food and shelter in parks and gardens and exposing humans to zoonotic agents that can be transmitted either directly by them or indirectly by their ectoparasites. In this review, we focus on the microorganisms detected in arthropods sampled from hedgehogs worldwide. Several microorganisms have been reported in ticks collected from these animals, including various Borrelia spp., Anaplasma spp., Ehrlichia spp., and Rickettsia spp. species as well as Coxiella burnetii and Leptospira spp. As for fleas, C. burnetii, Rickettsia spp., Wolbachia spp., Mycobacterium spp. and various Bartonella species have been reported. The detection of these microorganisms in arthropods does not necessarily mean that they can be transmitted to humans and animals. While the vector capacity and competence of fleas and ticks for some of these microorganisms has been proven, in other cases the microorganisms may have simply been ingested with blood taken from an infected host. Further investigations are needed to clarify this issue. As hedgehogs are protected animals, handling them is highly regulated, making it difficult to conduct epidemiological studies on them. Their ectoparasites represent a very interesting source of information on microorganisms circulating in populations of these animals, especially vector-born ones.

Haemaphysalis flava ticks as a competent vector of severe fever with thrombocytopenia syndrome virus

Severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne Bunyavirus, causes an emerging hemorrhagic fever in humans with a high fatality in Asia. The tick vectors and hosts of SFTSV are not well studied. We evaluated SFTSV transmission in laboratory reared Haemaphysalis flava ticks. RT-PCR demonstrated that after acquisition feeding in SFTSV-infected rabbits, 10 % (4/40) engorged larvae, 25% (5/20) engorged nymphs, and 50% (5/10) engorged females of H. flava became SFTSV RNA positive; after engorged larvae and nymphs molted into nymphs and adults, respectively, 12.5% (3/24) newly molted nymphs and 20% (2/10) newly molted adults were SFTSV RNA positive. Among 30 engorged females that oviposited, 10% (3/30) clutches of eggs and 3.3% (1/30) colonies of larvae were RNA positive for SFTSV. RT-PCR also showed that 6 days after being infested with SFTSV-infected ticks, 100% (3/3) rabbits infested with larvae, 100% (2/2) rabbits infested with nymphs, and 100% (2/2) rabbits infested with adult ticks became SFTSV RNA positive. In conclusion, H. flava can acquire SFTSV from infected rabbits by feeding; there is transstadial and transovarial transmission of the virus and all three stages of H. flava can transmit SFTSV to rabbits by feeding. Thus, H. flava tick is an effective vector of SFTSV and may play a role in the transmission of SFTSV in wild animals and humans.

Identification of Bacterial Communities and Tick-Borne Pathogens in Haemaphysalis spp. Collected from Shanghai, China

Ticks can carry and transmit a large number of pathogens, including bacteria, viruses and protozoa, posing a huge threat to human health and animal husbandry. Previous investigations have shown that the dominant species of ticks in Shanghai are Haemaphysalis flava and Haemaphysalis longicornis. However, no relevant investigations and research have been carried out in recent decades. Therefore, we investigated the bacterial communities and tick-borne pathogens (TBPs) in Haemaphysalis spp. from Shanghai, China. Ixodid ticks were collected from 18 sites in Shanghai, China, and identified using morphological and molecular methods. The V3-V4 hypervariable regions of the bacterial 16S rRNA gene were amplified from the pooled tick DNA samples and subject to metagenomic analysis. The microbial diversity in the tick samples was estimated using the alpha diversity that includes the observed species index and Shannon index. The Unifrac distance matrix as determined using the QIIME software was used for unweighted Unifrac Principal coordinates analysis (PCoA). Individual tick DNA samples were screened with genus-specific or group-specific nested polymerase chain reaction (PCR) for these TBPs and combined with a sequencing assay to confirm the results of the V3-V4 hypervariable regions of the bacterial 16S rRNA gene. We found H. flava and H. longicornis to be the dominant species of ticks in Shanghai in this study. Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria are the main bacterial communities of Haemaphysalis spp. The total species abundances of Proteobacteria, Firmicutes and Bacteroidetes, are 48.8%, 20.8% and 18.1%, respectively. At the level of genus analysis, H. longicornis and H. flava carried at least 946 genera of bacteria. The bacteria with high abundance include Lactobacillus, Coxiella, Rickettsia and Muribaculaceae. Additionally, Rickettsia rickettsii, Rickettsia japonica, Candidatus Rickettsia jingxinensis, Anaplasma bovis, Ehrlichia ewingii, Ehrlichia chaffeensis, Coxiella spp. and Coxiella-like endosymbiont were detected in Haemaphysalis spp. from Shanghai, China. This study is the first report of bacterial communities and the prevalence of some main pathogens in Haemaphysalis spp. from Shanghai, China, and may provide insights and evidence for bacterial communities and the prevalence of the main pathogen in ticks. This study also indicates that people and other animals in Shanghai, China, are exposed to several TBPs.

Comparative analysis of the anticoagulant activities and immunogenicity of HSC70 and HSC70TKD of Haemaphysalis flava

BACKGROUND

Haemaphysalis flava is a hematophagous ectoparasite that acquires the nutrition needed for development and reproduction by sucking blood and digesting the blood meal. During blood-sucking and blood-meal digestion, the prevention of blood coagulation is important for this tick. Previous studies have shown that heat shock cognate 70 (HSC70) protein has certain anticoagulant activities, but its immunogenicity remains unclear. Also, whether the mutation of individual bases of the TKD-like peptide of HSC70 through the overlap extension method can change its anticoagulant activities and immunogenicity remains to be investigated.

METHODS

The gene encoding the HSC70 protein was cloned from a complementary DNA library synthesized from H. flava. The coding gene of the TKD-like peptide of HSC70 was mutated into a TKD peptide coding gene (HSC70^TKD) using the overlap extension method. Escherichia coli prokaryotic expression plasmids were constructed to obtain the recombinant proteins of HSC70 (rHSC70) and HSC70^TKD (rHSC70^TKD). The purified rHSC70 and rHSC70^TKD were evaluated at different concentrations for anticoagulant activities using four in vitro clotting assays. Emulsifying recombinant proteins with complete and incomplete Freund's adjuvants were subcutaneously immunized in Sprague Dawley rats. The serum antibody titers and serum concentrations of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) were detected using an indirect enzyme-linked immunosorbent assay to assess the immunogenicity of rHSC70 and rHSC70^TKD.

RESULTS

The open reading frame of HSC70 was successfully amplified and found to have a length of 1958 bp. The gene encoding the TKD-like peptide of HSC70 was artificially mutated, with the 1373-position adenine (A) of the original sequence mutated into guanine (G), the 1385-position cytosine (C) mutated into G and the 1386-position G mutated into C. rHSC70 and rHSC70^TKD that fused with His-tag were obtained using the expression plasmids pET-28a-HSC70 and pET-28a-HSC70^TKD, respectively. rHSC70 and rHSC70^TKD prolonged the thrombin time (TT) and reduced the fibrinogen (FIB) content in the plasma, but did not affect the prothrombin time (PT) or activated partial thromboplastin time (APTT) when compared to the negative control. Interestingly, the ability of rHSC70^TKD to prolong the TT and reduce the FIB content in the plasma was better than that of rHSC70. The specific antibody titers of both rHSC70 and rHSC70^TKD in rat serum reached 1:124,000 14 days after the third immunization. The serum concentration of IFN-γ in the rHSC70^TKD group was higher than that in the rHSC70 group. The rHSC70 group has the highest serum concentration of IL-4, and the serum concentration of IL-4 in the rHSC70^TKD group was higher than that in the negative group.

CONCLUSIONS

rHSC70 and rHSC70^TKD exhibited anticoagulant activities by prolonging the TT and reducing the FIB content in vitro. rHSC70^TKD had better anticoagulant activities than rHSC70. Both rHSC70 and rHSC70^TKD had good immunogenicity and induced humoral and cellular immunity.

Wild Hedgehogs and Their Parasitic Ticks Coinfected with Multiple Tick-Borne Pathogens in Jiangsu Province, Eastern China

The increasing awareness of emerging tickborne pathogens (TBPs) has inspired much research. In the present study, the coinfections of TBPs both in ticks and their wild hedgehog hosts in Jiangsu province, Eastern China were determined by metagenome next-generation sequencing and nested PCR. As a result, Rickettsia japonica (81.1%), novel Rickettsia sp. SFGR-1 (5.1%), Anaplasma bovis (12%), A. platys (6.3%), novel Ehrlichia spp. Ehr-1 (16%) and Ehr-2 (0.6%), E. ewingii-like strain (0.6%), Coxiella burnetii (10.9%), and a novel Coxiella-like endosymbiont (CLE) strain (61.1%) were detected in Haemaphysalis flava ticks. A. bovis (43.8%), Ehrlichia sp. Ehr-1 (83.3%), and C. burnetii (80%) were detected in Erinaceus amurensis hedgehogs. Coinfection rates with various TBPs were 71.5% and 83.3% in ticks and hedgehogs, respectively, both with double-pathogen/endosymbiont coinfection rates over 50%. We found the following. (i) Er. amurensis hedgehogs seem to contribute to the natural cycles of R. japonica, A. bovis, Ehrlichia sp., and C. burnetii and may be reservoirs of them except for R. japonica, and A. bovis is proved to infect hedgehogs for the first time. (ii) H. flava is proved to harbor various TBPs as a reservoir host, including CLE identified for the first time, which could inhibit coinfection of C. burnetii while promoting that of Rickettsia spp. in H. flava. (iii) Four novel TBP species were identified. This study provides useful epidemiological information crucial for assessing the potential infection risks to humans, thus benefiting the development of strategies to prevent and control tick-borne diseases. IMPORTANCE In the present study, we found the following. (i) Er. amurensis hedgehogs seem to contribute to the natural cycles of R. japonica, A. bovis, Ehrlichia sp., and C. burnetii and may be reservoirs of them except for R. japonica, and A. bovis is proved to infect hedgehogs for the first time. (ii) H. flava is proved to harbor various tickborne pathogens (TBPs) as a reservoir host, including Coxiella-like endosymbiont (CLE) identified for the first time, which could inhibit coinfection of C. burnetii while promoting that of Rickettsia spp. in H. flava. (iii) Four novel TBP species were identified. This study provides useful epidemiological information on TBPs harbored and transmitted by ticks and their hosts, for assessing the potential infection risks to humans, thus benefiting the developing strategies for tick-borne diseases prevention and control.

Molecular detection of spotted fever group rickettsiae in hedgehogs (Erinaceus amurensis) and hedgehog-attached ticks in Xuyi County, Southeast China

Tick-borne diseases like Rickettsia, Anaplasma and Ehrlichia are widespread infectious zoonoses that threaten the health of both humans and animals worldwide. Ticks and their hosts, such as hedgehogs, can play a crucial role in transmitting tick-borne diseases and the cycle of Rickettsia. To investigate the presence and identity of Rickettsia in hedgehogs and hedgehog-attached ticks in Xuyi County, Southeast China, 114 ticks were collected from 45 hedgehogs captured totally. Via morphological and molecular methods, all these ticks were identified as two species: Haemaphysalis flava (110/114, 96.5%) and Haemaphysalis longicornis (4/114, 3.5%). Rickettsia spp. were genotypically characterized by PCR targeting rrs, gltA, ompA, ompB, and sca4 gene fragments. The prevalence of spotted fever group rickettsiae (SFGR) infection found in hedgehogs and ticks was 17.8% (8/45) and 78.1% (89/114), respectively. Phylogenetic analyses demonstrated that those Rickettsia spp. belong to two species: Rickettsia heilongjiangensis (R. heilongjiangensis XY-1) and a potential new species, Candidatus Rickettsia xuyiensis XY-2. The present study gave the first evidence of R. heilongjiangensis and Candidatus R. xuyiensis in ticks and hedgehogs of Southeast China. Our findings suggest that hedgehogs might be involved in the natural transmission cycle of Rickettsia species.

Co-existence of Multiple Anaplasma Species and Variants in Ticks Feeding on Hedgehogs or Cattle Poses Potential Threats of Anaplasmosis to Humans and Livestock in Eastern China

Background

Anaplasma spp., causative agents of anaplasmosis, pose significant a threat to public health and economic losses in livestock farming. Co-infections/co-existence of various Anaplasma spp. may facilitate pathogen interactions and the emergence of novel variants, represent potential dangers to public health and economic losses from livestock farming, and raise challenges of detection and diagnosis. The information regarding co-infection/co-existence of Anaplasma in their vector ticks and wild animals is limited and needs urgent investigation.

Methods

Wild hedgehogs and ticks from hedgehogs and cattle were collected from Jiangsu province, Eastern China, and DNA was extracted from hedgehog organs and tick homogenates. Various genera of species-specific polymerase chain reaction (PCR) or nested PCR amplifications targeting 16S ribosomal RNA (rrs), msp4, or groEL gene coupled with sequencing were conducted to identify Anaplasma spp.

Results

Anaplasma phagocytophilum (1, 0.6%), A. marginale (2, 1.2%), A. platys variants xyn10pt-1 (13, 7.7%), xyn21pt-2 (3, 1.8%), and xyn3pt-3 (3, 1.8%), A. bovis variant cwp72bo-1 (12, 7.1%), and a novel Candidatus Cryptoplasma sp. (1, 0.6%) were identified in 168 Haemaphysalis longicornis ticks from cattle. A. platys variant xyn10pt-1 (20, 11.4%) and A. bovis variants cwp72bo-1 (12, 6.9%) and cwp55-36bo-2 (1, 0.6%) were detected in 173 H. flava ticks from hedgehogs. However, only A. bovis variant cwp72bo-1 (15, 46.7%) was identified in 32 Erinaceus amurensis hedgehogs. Various co-existence combinations were found only in ticks.

Conclusion

The co-existence of various Anaplasma spp. and variants in H. flava and H. longicornis was detected for the first time in the world. The high infection rate of A. bovis in hedgehogs and its moderate infection rate in their parasitic ticks suggest that Er. amurensis hedgehog could be an important reservoir of A. bovis, rather than A. platys. Horizontal transmission of Anaplasma spp. may exist among different tick species via their shared hosts in the investigated area. This study provided epidemiological data that could be crucial for strategy development for early warning, prevention, and control of potential Anaplasma infections.

The Role of Ranged Horses in Eco-Epidemiology of Rickettsia raoultii Infection in China

Rickettsia raoultii is a tick-borne pathogen that infects humans; however, the vertebrate hosts of this pathogen have not been clearly defined. Our molecular examination of Rickettsia spp. infecting mammals and ticks in China, identified the gltA, ompA, and 17KD gene sequences of R. raoultii in horses and their ticks. This indicates a role of horses in R. raoultii epidemiology.

Microorganisms associated with the North African hedgehog Atelerix algirus and its parasitizing arthropods in Algeria

Hedgehogs are small mammals. They are potential reservoirs of various zoonotic agents. This study was conducted in Bouira, a north-central region of Algeria. A total of 21 Atelerix algirus corpses were picked up on roadsides and gardens. Hedgehog kidneys, spleens and ectoparasites were collected. Twelve hedgehogs were infested with ectoparasites, including Archaeopsylla erinacei, Rhipicephalus sanguineus s.l. and Haemaphysalis erinacei. Hedgehog organs and randomly selected arthropods were screened for microorganisms using molecular methods. Coxiella burnetii was detected in kidneys, spleens, A. erinacei, Hae. erinacei and Rh. sanguineus s.l. Leptospira interrogans was detected in kidneys. Rickettsia felis and Rickettsia massiliae were detected respectively in A. erinacei and in Rh. sanguineus s.l. DNA of an uncultivated Rickettsia spp. was found in Hae. erinacei. Wolbachia spp. DNA was detected in fleas. The DNA of potential new Bartonella and Ehrlichia species were found respectively in fleas and ticks. This study highlights the presence of DNA from a broad range of microorganisms in hedgehogs and their ectoparasites that may be responsible for zoonoses in Algeria.

Atelerix algirus, the North African Hedgehog: Suitable Wild Host for Infected Ticks and Fleas and Reservoir of Vector-Borne Pathogens in Tunisia

Small wild mammals are an important element in the emergence and transmission of vector-borne pathogens (VBPs). Among these species, hedgehogs have been found to be a reservoir of VBPs and host of arthropod vectors. Surveillance of VBPs in wildlife and their arthropods are crucial in a one health context. We conducted an exploratory study to screen Atelerix algirus hedgehogs and their infesting ticks and fleas for VBPs using a high throughput microfluidic real-time PCR system. Tested biopsies from hedgehogs were found to be naturally infected by Theileria youngi, Hepatozoon sp., Ehrlichia ewingii, Coxiella burnetii, and Candidatus Ehrlichia shimanensis. Similarly, Haemaphysalis erinacei and Rhipicephalus sanguineus tick species were infected by Ehrlichia ewingii, Rickettsia spp., Rickettsia massiliae, Borrelia sp., Coxiella burnetii, Rickettsia lusitaniae and Anaplasma sp. Archaeopsylla erinacei fleas were infected by Rickettsia asembonensis, Coxiella burnetii, and Rickettsia massiliae. Co-infections by two and three pathogens were detected in hedgehogs and infesting ticks and fleas. The microfluidic real-time PCR system enabled us not only to detect new and unexpected pathogens, but also to identify co-infections in hedgehogs, ticks, and fleas. We suggest that hedgehogs may play a reservoir role for VBPs in Tunisia and contribute to maintaining enzootic pathogen cycles via arthropod vectors.